POS0008 THE UTILITY OF TRANS-BRONCHIAL LUNG BIOPSIES TO GUIDE THE TREATMENT IN PATIENTS WITH RHEUMATIC INFLAMMATORY DISEASES: A RETROSPECTIVE CROSS-SECTIONAL STUDY
Authors: M. Andersen, T. K. Lund, T. H. L. Jensen, M. Iversen, M. Perch, B. Baslund
Journal: Annals of the Rheumatic Diseases (2022)

Background Rheumatic inflammatory disease associated interstitial lung disease (R-ILD) is associated with significant mortality and morbidity 1 . On a patient-to-patient level, imaging which is a cornerstone in diagnosing R-ILD may not be sufficent to determine the underlying cause of the imaging pathology or the degree of reversibilty. Furthermore the precense of co-morbidity and diffential diagnoses such as infections or malignacy needs to be taken into account when dertemining the therapeutic strategy. The role of transbronchial lung biopsies (TBB) in the diagnostic workup of R-ILD is unclear and TBB is not generally recommended 2-4 . Objectives The study objective was to examine the utility of TBB to guide treatment in a population of patients with R-ILD reffered for bronchoscopy. Methods All patients from the Department of Rheumatology, Rigshospitalet, Copenhagen, Denmark referred for a TBB on the suspicion of R-ILD, from 2002 to 2016 were identified. Patient demographics as well as smoking status, previous lung disease, pulmonary function test, CTD-diagnosis, imaging results and immunomodulatory therapy pre- and post-bronchoscopy were obtained. Histology findings were used to dichotomize patients into a high inflammatory group or a low inflammatory group. The high inflammation group primarily consisted of non-specific interstitial pneumonia (NSIP), organizing pneumonia (OP), lymphocytic infiltrating pneumonia (LIP) and granulomatous inflammation whereas the low inflammation group primarily consisted of histological findings of usual interstitial pneumonitis (UIP) and biopsies describing fibrosis and/or sparse unspecific inflammation. Therapeutic consequence was defined as intensification of therapy. Differences in treatment intensification were calculated using a binominal logistic regression model. Differences in treatment intensification were calculated using a binominal logistic regression model adjusted for age, gender, smoking status, previous lung disease, diffusion capacity, rheumatologic diagnose, c-reactive protein level prior to TBB. Covariates with P&gt;0.1 were excluded by a stepwise ‘backwards’ elimination. Results 96 patients had TBB performed. Biopsies from 55 patients were categorized as high-inflammatory and 41 as low-inflammatory, respectively. In the high inflammatory group thirty-eight (69%) had their therapy intensified compared to 6 (14%) in the low-inflammatory group (P &lt;0.001). TBB inflammation type was the only covariate that was significantly associated with treatment intensification. No procedure related complications were registered. Conclusion TBB findings can guide treatment strategy in R-ILD patients with suspected activity in the pulmonary disease. TBB appears safe and could be considered as part of the diagnostic workup in patients with inflammatory rheumatic diseases where clinical features, bloodsamples, imaging and/or pulmonary function test do not provide suffcient information to guide the therapeutic strategy. References [1]Mathai SC, Danoff SK. Management of interstitial lung disease associated with connective tissue disease. BMJ. 2016;352:h6819. doi: 10.1136/bmj.h6819 [doi]. [2]Sebastiani M, Faverio P, Manfredi A, Cassone G, Vacchi C, Stainer A, et al. Interstitial Pneumonia with Autoimmune Features: Why Rheumatologist-Pulmonologist Collaboration Is Essential. Biomedicines. 2020;9(1). Epub 2020/12/31. doi: 10.3390/biomedicines9010017. PubMed PMID: 33375368; PubMed Central PMCID: PMCPMC7824155. [3]Mochimaru H, Kawamoto M, Enomoto T, Saitoh Y, Abe S, Nei T, et al. Transbronchial biopsy is clinically useful in classifying patients with interstitial pneumonia associated with polymyositis and dermatomyositis. Respirology. 2008;13(6):863-70. [4]Morell F, Reyes L, Domenech G, De GJ, Majo J, Ferrer J. [Diagnoses and diagnostic procedures in 500 consecutive patients with clinical suspicion of interstitial lung disease]. Arch Bronconeumol. 2008;44(4):185-91. Disclosure of Interests Martin Andersen Employee of: Novo Nordisk A/S: 2010-2015, Thomas K. Lund: None declared, Thomas H. L. Jensen: None declared, Martin Iversen: None declared, Michael Perch Speakers bureau: Mallinckrodt, Novartis, GSK, PulmonX, Consultant of: Ambu, PulmonX, Takeda, Grant/research support from: Roche, Bo Baslund: None declared